Solar Charging

Discussion in 'Tech/Mech General' started by Dave Flegg, Apr 27, 2016.

  1. Dave Flegg

    Dave Flegg Funster

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    i have 2 X 110ah leisure batteries fitted to my van (all factory wired).

    I fitted last year a 100w 10A dual output (1 for leisure and 1 for cab battery) solar charger which connect into the PSU2007 unit on my van via manufacturer supplied cable. This has been set for 70/30% in favour of leisure batteries as it charges both of them as if they were one according to PSU manufacturer person.

    What I want advice on is how good should this charge my leisure batteries. What current when charging (assuming very sunny) should I expect to get as is and also if I was to change the control unit to 20A would provide any benefit (Ie quicker charging) or do I need to add another 100w panel to make any gains. I have seen on he solar display the max current as 6.5A so as is 20A wouldn't be needed.

    Is this set up suitable for 2 X 110 leisure batteries. I do weekends of rough camping relying only on leisure batteries and sun shine.

    Just thinking of upgrading the system if anyone thinks it could be beneficial but wasn't sure what gains I could expect and what I actually need to upgrade.

    Any words of wisdom appreciated.

    Many Thanks.

    Dave.
     
  2. John Laidler

    John Laidler Funster

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    How much current you get depends on load and the state of the batteries. If the batteries are fully charged and everything is turned off then you might see a charging current of only a fraction of an amp.

    A 100W solar panel can in theory produce around 8 amps or so, depending on the battery voltage at the time but that will be at the equator with a nearby star going conveniently supernova.

    If you are talking about the UK then realistically you won't see much more than two or three amps maximum most of the time.

    It isn't really possible to say whether you need to upgrade, which would be by adding a second panel and probably not touching the controller anyway, without knowing what load you have on the system.

    What you have may be perfectly adequate. I can only suggest give it a try but if you find your batteries going a bit flat I would change the charging regime to 100% leisure - the vehicle battery should be fine over a weekend if not a month or more - again depending on the loads, such as any alarm system.
     
    Last edited: Apr 27, 2016
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  3. tonyidle

    tonyidle Funster

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    I'd suggest 10% would be more than enough for the starter battery - readjust to 50% if the van is parked up during winter.
     
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  4. Dave Flegg

    Dave Flegg Funster

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    DBK, Tonyidle. Cheers for that info. I will change the setup to 90% in favour of the leisures. The van has an alarm which even when off is still actively draining the battery a little son is like to give it a bit of charge. I know if my leisures are full the unit should switch to giving more to the cab battery anyway.

    My concern was my system doesn't seem to work as well as my brothers on his old Kontiki with 1 leisure battery. He seems to have loads more Lecky than I get with a similar solar setup on my auto trail scout. Only difference we have on solar is his panel and his direct connection to his batteries, cab and leisure. Just didn't know if my system was doing its job well enough.
     
  5. Dave Flegg

    Dave Flegg Funster

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    Batteries are 1 yr old. Load is mainly lighting and water pump. Radio. Phone charging and a bit of TV.

    I have noticed I get a fair bit of drain. The solar manages this when the van is hardly used but struggled at the end of August last year when I had been watching tv for a couple of hours and then sat in the van with music and lights on. Power dropped really low. I seem to lose a volt over night (based on built in panel reading) but when adding an amp metre in line with nothing on I show a load of 0.07A which seems fine and load testing each electrical item in my van separately showed nothing stood out as excessive really.
     
  6. TheBig1

    TheBig1 Funster Life Member

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    i personally think you are being unrealistic. expecting more than 4 amps charge rate this time of year it will take many hours to recharge your batteries, longer than 3 or more days good sunshine in the uk
     
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  7. TheBig1

    TheBig1 Funster Life Member

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    assuming 50% discharge, you need to replace 110ah. if the panel supplied 1amp then it would take 110 hours, 2amps 55hours, 4amps 27hours to fully recharge. take out more amp/hours out of the battery than replaced each day and the batteries go flat
     
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  8. Dave Flegg

    Dave Flegg Funster

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    I'm liking the answers folks thanks. Helps me get my head round it. My main question really is adding another panel, doubling the current produced. Is it worth it?
     
  9. TheBig1

    TheBig1 Funster Life Member

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    yes, maybe an even bigger panel if it will fit
     
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  10. John Laidler

    John Laidler Funster

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    We had a 100W panel and it was sufficient for lights, TV, water pump etc. I only needed to add a second panel when I started using an electric cool box.

    Assuming you arrive with fully charged leisure batteries I am surprised you can't last a weekend. Do you have led lighting? Not that in August you are going to be using much lighting anyway.

    A second panel will help but it won't do much in winter.

    I would try and work out where the power is going first. Do you have an ammeter and voltmeter in the system? If so what sort of readings do you get? For example, when you arrive and everything is charged up the voltage should be around 13.8 and in the middle of the day with just a TV on and a bit of phone charging the system should be holding its own with no voltage loss. Once the sun has gone down you will see a drain, but it should only be an amp or two. What figure do you see?
     
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  11. Dave Flegg

    Dave Flegg Funster

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    DBK. Thanks. I have checked every appliance in my van for load levels with a DVM in line. Here are the results. Only my lights caused concern unless you spot something. I'm was trying to work out where I could do this with both batteries connected and the load being across them both.
     
  12. Dave Flegg

    Dave Flegg Funster

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    For info I also tried loaded up my batteries for 4 hours. I started at just over 13V (taken from van display and turned both TV's on with solar connected in the dark so not charging and all lights including locker lights etc. More than I'd ever have on at once. After 4 hours one TV wouldn't turn back on after it went off but other worked ok and all lights were on although dimmer than when mains reconnected. Battery levels showed over 8V until lights turned off and went back to 10.5V. I know this may shaft batteries but I'm trying to prove they're at fault as something has to be hence thinking about adding more solar charge capabilities to help recover them.

    What do you think.
     
  13. John Laidler

    John Laidler Funster

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    I'm not sure your table tells me a lot and I don't understand the right hand column. However, from it I can see if you ran your TV for 12 hours a day then that would equal about 30 Ah which is what you might expect from your solar panel on a nice sunny day. Add the reserve you have in your batteries, which is about 100 Ah without flattening them completely then you should be good for a weekend.

    It is possible your batteries are goosed despite being new. This might have happened if they were allowed to run totally flat.

    Edit: Just read your post above. Your batteries are probably gone I fear. You shouldn't let them go much below 12 volts if at all possible and at say 11.5 you need turn everything off.
     
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  14. Terry

    Terry Funster

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    Hi Dave LET ME START BY SAYING i DON'T DO LECCY AT ALL BUT DO UNDERSTAND A FEW BASICS SO HERE GOES iF YOUR BATTS ARE DOWN TO 10.5 THEY ARE MORE THAN LIKELY FUBBERED oppps caps -Now best to give them a full charge off the van then test -IT COULD BE YOUR CHARGE CONTROLLER THAT IS CAUSING YOUR BATTS TO discharge in the dark or simply batts no good To check you can make sure they are fully charged in daytime then simply disconnect the solar for the night -2 batts should keep all your leccy going all day and night (24 hrs) Worth checking because 2 batts cost over £100 while a new charge controller is only £10 / £30 unless you want a all singing dancing one like some then it's getting crazy money close to £180
    terry
    BTW your tv will loose pic long before sound so if pic goes you know the battery is close to flat
     
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  15. funflair

    funflair Funster Life Member

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    YES
     
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  16. Terry

    Terry Funster

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    (y)(y)(y) but no good if the charge control is back charging at night or batts no good -needs sorting first
    terry
     
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  17. funflair

    funflair Funster Life Member

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    But he will still have twice as much solar as before and thats not a bad thing, yes if there is a problem it needs sorting but he seems to have checked for a drain and found nothing so most likely batteries Kna-----d. When he gets new batteries on he will be able to keep them fully charged off two panels which is better for them than running too low.

    Martin
     
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  18. weejohnw

    weejohnw Funster

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    Hi, grey cells prevent me from fully understanding the amps/volts discussions, however, I have two 110 amp leisure batteries and a 140 volt solar panel and wild camp all the time. Even on the odd occasion when we do use a site, we seldom use ehu unless it is in the price. Phone/camera/torch chargers - some charged on a 300w inverter and perhaps a few hours TV watching and we have never run down the batteries - even in winter and that is here on the Emerald Isle where sunshine can be quite lacking at times. LED lights area great way of limiting battery usage too. The longest we have stayed put in one location is about two weeks and never had an issue or worried about running down the power supply. Hope this helps.
     
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  19. Lenny HB

    Lenny HB Funster

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    Like others have said your batteries have had it.
    @DBK you have been working out your figures at 12v a solar regulator needs around 15-16v input to work giving you a max output from a 100 W panel of around 6.25 - 6.5 amps and you will only get that a 2-3 hours around midday in June and July on a bright sunny day with clear skys.

    If you are only doing weekends your set up should be fine once you have changed your batteries. You could change the regulator to a MPPT type this would give better output in lower light levels & help extend your season.
     
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  20. John Laidler

    John Laidler Funster

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    Dave, there might be a bit of information overload here so I suggest get your batteries checked as a first step. Then if you buy new ones, which I suspect you need if they can't run two TVs for four hours and then give it another go and see how you get on but under no circumstances let the voltage drop below 11.5. I start getting worried if mine fall below 11.9 volts.

    If you find you still can't last a weekend then further investigation is needed as I think should be able to.

    Another panel and possibly a new controller will give more power but if you don't need them why bother? You could have a thousand watts on the roof but if the batteries are shot they will still go flat when it gets dark which is why you need to address the batteries first.
     
    Last edited: Apr 28, 2016
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